Diversity method antenna devices have been conventionally known that have a plurality of antennas with different reception characteristics and directivities, and select therefrom an antenna in the best communication condition to receive radio waves (see JP 2002-237773, A and JP 2002-271125, A, for example).
In the diversity method antenna devices, the plurality of antennas are connected to a radio module through coaxial cables, and one or more of the antennas in good communication conditions are selected by the radio module. Therefore, good communication condition can be obtained even in the case where reception radio waves vary in arrival direction with surrounding environments or the case where reflected waves or diffracted waves of the radio waves are received.
An antenna device has been known in which an antenna is containably attached to a case and the antenna can be taken in and out of the case if necessary (see JP 9-246824, A). As shown in FIG. 18, the antenna device includes a telescopic antenna 9 slidably projecting from an end of a case 8. A recess 81 is defined at the end of the case 8, and an opening 82 is defined at a bottom of the recess 81. Inside the case 8, a cylindrical antenna holder 83 is attached facing to the opening 82. The antenna 9 has a first rod 91 having the largest diameter among a plurality of telescopic rod portions 91, the first rod 91 coupled to an antenna base 93 through a hinge mechanism 92. The antenna base 93 is slidably held by the antenna holder 83, and can rotate on the sliding direction.
In the antenna device, if radio waves need not be transmitted nor received, the antenna 9 is contained inside the case 8. If radio waves need be transmitted or received, the whole antenna 9 is first exposed from the case 8, the rod portion 91 is subsequently rotated on a rotation axis of the hinge mechanism 92, and the rod portion 91 is thereafter extended. This enables the antenna 9 to transmit and receive radio waves. In this state, the antenna 9 can be rotated by the hinge mechanism 92 so as to be close to or apart from the case 8, while the antenna 9 can rotate on a central axis thereof to vary directions of the rotation axis of the hinge mechanism 92. The antenna 9 can be thereby directed in a direction of the highest reception sensitivity to thereby obtain a good communication condition.
However, if a diversity method antenna device is attached for use to for example a cabinet of a television receiver, the antenna device will be attached in a position projecting from the cabinet in order for a plurality of antennas to be in good radio wave reception conditions. Therefore, there has been a problem of obstruction as the antenna device always projects from the cabinet even if radio waves need not be transmitted nor received.
Accordingly, a collapsible antenna device may be possible in which a pair of cases are openably and closably connected through a hinge mechanism similar to the hinge mechanism provided in the antenna device of FIG. 18, and one case contains a plurality of antennas, while the other case contains a radio module, the other case being fixed to a cabinet. In the antenna device, the antennas can be set to project from the cabinet by opening the both cases when radio waves are transmitted or received, and the antennas can be collapsed by closing the both cases when radio waves need not be transmitted nor received.
However, in the antenna device as described above, a plurality of cables for connecting the plurality of antennas to the radio module pass through the hinge mechanism, and therefore the plurality of cables are likely to be entangled with each other by rotation operation of the hinge mechanism accompanying opening and closing operation of the both cases to thereby cause troubles in rotation operation of the both cases.
Accordingly, an object of the present invention is to provide an antenna device capable of being collapsed if necessary, in which a plurality of cables extending between a plurality of antennas and a radio module are not entangled with each other with collapsing.